Change system



Pntvnted June 17, 1919.

4 SHEElS-SHEET l.

F. LUEBEHGLR.

SEM-AJYUWAUC EL'LPHONE EXCHANGE SYSTEM.

APPLICATION mso lung n. 191g. RENEww APN. 12.1919. 1,306,824.

F. LUBBERGER.

SEMI-AUTOMAIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION man Juni 1e, 1910. www APR.12.19\9.

F. LUBBERGER.

SEMI-AUTOMATIC ELlPHONE EXCHANGE SYSTEM.

APPLlcMlon mm wuz ls. |910. neuneu Avn. 12.1919.

Patented June 17, 1919.

4 SHEETS'SHEE 3.

F. LUBBERGER. SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM. Arvucmon mw luna 11s. 1910. www A1111. 12. 191s.

1 ,306,824. Patented June 17, 191).

4 SHEETS-'SNEE 4.

WWA/55555 /fx/x/f/s/Tofi).e

UNITED sTA'rnsfATENT OFFICE.

FRITZ LUBBEBGER, OF CHICAGO, IILINOIS, ASSGNOB. TO AUTOMATIC ELECTRIC (2mm, .0F CHICAGO, ILLINOIS, Ai CORPORATION Ol' ILLINOIS.

SE'lI-iAUTOIATIC TELEPHONE-EXCHANGE SYSTEM.

Patented June 17, 1919.

Application led June 16, 1910, Serial H0. 567 ,298. Renewed April 112, 1919. Serial Ko. 289,74.

T o all wie o m 'it may concern Be it known that I, Fnrrz LUBBERGER, a subject of the Emperor of Germany, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Semi-Automatic Telephone- Exchange Systems, of which the following is a specification.

My invention relates to automatic or semiautomatic telephone exchange systems. It relates more particularly to semi-automatic systems in which the calls are answered by an operator, and in which the latter is provided with means for controlling one or more automatic switches to extend or complete the calls. Ordinarily this is accomplished by a cord circuit which is included in the calling connection.

An object of my invention is, therefore, to provide an arrangement whereby an operator at one exchange may, through the medium of a trunking connection, control the establishment of connection between calling and called lines of another exchange, which calling connections exclude the trunking connect ion, the talking circuits being confined en ti rely to the exchange at which the calling and called lines terminate, whereby the operator may release the said trunking connect-ion after connecting two lines together at the other exchange, and then use the same trunkng connection for answerin other calls, thus making it possible to ispense with operators at the exchange where the calling and called lines` are located.

It will be seen that an arrangement of this kind is of considerable advantage in a. system in which there is a branch exchange at which manual lines terminate, and which is not large enough to warrant the employment of an operator to answer the calls. In such case, and by the provision of my invention, the calls at the branch exchange are answered by an operator at the main exchange, and the calling and called lines at the branch exchange are connected together without the necessity of havin the calling connection extend through t e main exchange, the trunking connection to the operators board aty the mainexchange being excluded from such calling connections, and being used only for answering the calls and then controlling the automatic switches at the branch exchange to find the called lines, or to extend the calls. Y

Another object is to provide an improved connector for use in a system of this kind adapted especially for use when one partyline subscriber calls another on the same line, the said connector being provided with improved means for enabling it to seize the calling party line. which is also, in the case of a reverting call, the called line as well, as will hereinafter more fully appear.

To the foregoing and other useful ends my invention consists in matters hereinafter set forth and claimed.

i In the accompanying drawings Fifrure 1 shows diagrammatically a subscribers sub4 station A with its line switch C, a. master switch D for controlling the group of line switches of which the switch C is a member, and two connector switches E and F, in a system embodying the principles of my invention. At L iS shown a ringer generator, and at I and I' are represented two busy signaling machines. There may, however, be but one such busy machine.

In Fig. 2 is shown a subscribers substation A', a line switch H and an operators cord circuit O of said system.

liig. 3 shows more in detail the mechanism and circuits of the master switch D.

Fig. 4 is a simplified diagrammatic representation of a complete system embodying the principles of my invention.

Figs. 5, 6 and 7 are circuits of apparatus employed in the system and will be more fully described hereinafter.

The subscribefs substation shown at A in Fig. 1 may be any suitable common battery manual substation to which has been added the push button 2 and resistance coil 3. The substation A comprises the usual receiver 4. switch hook 5. transmitter 6` ringer 7 and condenser 8. iVhen the receiver is removed from the switch hook the hook 5 engages the contact point 9, thereby bridging the transmitter 6 and receiver 4 in series across the line conductors 10 and 11. VVheu the push button 2 is depressed it separates the springs 12 and 13. whereby the resistance 3 is included in the bridge across the line conductors 10 and 11.

'The line switch C comprises an electromagnet 23 and a plunger (not shown) attached to the plunger arm 14 and adapted to be thrust into a bank of contacts comprising the springs 15. 16, 17, 18, 19, 20, 21 and 22. The electromagnet 23 comprises four windings, viz: a pull-in windin 24, a bridge-cutotf winding 25, a line win lng 28 and a holding winding 27. The magnetic circuit of the windings 28 and 27 is separate from that of the windings 24 and 25. The general operation of the line switch C is as follows: Then the receiver at the calling substation 'is removed from the switch hook, thereby bridging the talking circuit across the line. conductors, an energizing circuit is established through the line winding 28. The winding 28 attracts the armature 99, which presses the springs 29 and 30 into contact, whereby an energizing circuit is closed through the windings 24 and 27. The winding 24, upon energizing, attracts the plunger arm 14 and the cut-olf amature 31. The lunger arm 14 thrusts the plunger into the ank of an idle trunk and the cut-olf armature cuts the line winding oil' from the line conductors. Then the plun r enters the bank a circuit is closed throu the cutoif Winding 25, which holds the plunger arm 14 and the amature 31 in their at-` tracted positions until the switch is released.

The master switch D (shown more in detail in Fig. 3) is a somewhat modified form of the general type disclosed in the Western Electr'fm of Chicago, Illinois, of January 25, 1908, and in the American Telephone Journal of New York, N. Y., of June 6, 1908. The said'master switch D comprises the motor magnet 32 adapted to operate the ratchet wheel 33, which in turn operates the plunger shaft 34. through the medium of the arm 35 and connecting shaft 36. The master switch bank M is composed 0f the individual segments a and the common segment b. The wiper 37 is adapted to keep some one of the individual segments a: in electrical connection with the common segment b. The motor ma et relay 38 closes an energizing circuit t )rough the motor magnet 32. The motor magnet relay is in turn energized by the busy trunk relay 39. At the top of the connecting shaft 36 is a spacing cam or segment 40 having on its arc ten circular openings adapted to fit the pin 41 at the extremity of the armature 42'l of the motor magnet relay 38. This spacing cam 40 is faste-ned to t-he shaft 36 and rotates with it. lVhen a trunk upon which is resting the wiper 37 is seized the busy trunk relay 39 is energized. The relay 39, upon energizing, closes an energizing circuit for the motor magnet relay 38. The relay 38 then attracts its amature 42, which withdraws the linger 41 from the particular opening in the cam 40 in which it happens at the time to be resting. Also, at the same time an energizing circuit is closed through the motor magnet 32. The motor magnet 32, being provided with interrupter springs, operates in a manner similar to that in which a. buzzer operates as long as its energizing circuit remains closed. As soon as the motor magnet begins to operate the opening in which the pin 41 was resting is moved out of register with said pin and the motor magnet cannot then stop operating until the.pin 41 engages the next opening in the spacing cam 40, when the shaft becomes locked and cannot be moved again until the relay 38 is energized.

The connector switch E is of the general type disclosed in United States Letters Patr ent No. 815,176, granted March 13, 1906, to Keith, Erickson and Erickson, and, as shown, is modified to operate in connection with a two-wire common battery system. Among other details it embodies the following features: The switch shaft (not shown) carries the wipers 43, 44, 45 and 45a. The side switch is well known and comprises the switch wipers 46, 47, 48, 48I and 49 which are under the control of the private magnet 50. The operation of the connector is controlled by the operator at the main exchange through the medium of the relays 51. and 52. When the side Switch is in first. position the relay 51 controls the vertical magnet 53, the purpose of which is to give the shaft and shaft wipers 43, 44, 45l and 45 a vertical motion. The rotary magnet 54 imparts a rotary motion to the shaft and shaft wipers and is controlled by the relay 51 when the side switch passes to the second position. The private magnet is under the direct control of the private magnetrelay The means whereby the connector may be restored to normal position is provided by the release magnet 56. which isconnccted with the battery lead through the norma-l springs 57 and 58 when the shaft is raised one or more steps. The operation of the release magnet 56 is under the direct control of the slow acting release relay 50. The ringer relay 60 operates to connect the linger generator L with the line of the called subscriber. Then theringer relay operates, one side of the ringing circuit is grounded through the condenser 61. The condensers 62 and 63 divide the talking circuit through the connector E into two parts.

The connector l" is of the same general type as the connector E, but is more in the nature of a local battery switch in that it does not furnish talking battery current to either substation. When the switch F is used in a connection the two substations rc ceive their talking battery current from the main exchange. The connector F comprises the usual shaft wipers 64, 65 and 66, vertical magnet 67, rotary magnet 68. private magnet 69 and release magnet 70. This conntor is operated by the operator at the main exchange by ground impulses over one side of the line through the relay 71. The switch F is provided with the usual slow acting release relay 72 and private magnet relay 73. Each point of the private bank of the connectors F and E comprises two separate contacts insulated from each other and each connected to separate springs of the bridge-cut-oli` rela. s of the line switches. The line switch H 1s of the same type as the line switch C (Fig. 1). The plunger of the line switch H is self alining-that is, wheneverthe plunger of the switch H is withdrawn from the bank it immediately assumes a position opposite the same trunk before which the plungers that are in locked engagement with the plunger shaft are held.

The plunger of the switch H is controlled by the same master switch D that controls the plungers of the line switches C, but the line switch H has an auxiliary master switch bank M which is similar to the master switch bank M (Fig. 1). The line switch H is allotted to a trunk which ends at the main exchange in a key K'. From the bank terminals of the line switch H trunks lead to the connector switches E.

The opemtors cord circuit O may be of any suitable or approved type of manual common battery operators cord circuit. As here shown, the cord O comprises the usual supervisonvr relays' 76, 77, 78 and 79, lamps 80 and 81, keys K2, K3 and K* and con- Vdensers-Z and 83. The opcrators telephone set Q, in addition to the usual transmitter 84. receiver 85 and induction coil 86, is equipped witha calling device 87 for operating the automatic switches at the branch exchange. The substation A' is an ordinary manual substation comprising a receiver 88, transmitter 89, condenser 90, ringer 91 and switch hook 92.

In order to give a clearer understanding of my invention I will first describe how the operator at the main exchange may operate the branch exchange switches to eliect a counection between the branch exchange substation A and a substation of the main exchange, or of another branch exchange. It will be assumed that the subscriber at substation A on line #44 desires to communicate with the main exchange substation A.

When the subscriber at substation A removes his receiver from the switch hook preparatory to making a call an energizing circuit is closed through the line winding 28 of the line switch C. The energizing circuit of the winding 28 extends from ground G through springs 29 and 93 to line conductor 11, thence through the switch hook 5, contact point V9, receiver 4, push button springs 12 and 13 and transmitter 6 of substation A to line conductor 10, thence through springs 95 and 94, line winding 28, spring 115, armature 42* to the battery lead, thence through battery B to ground G. The line winding 28, upon energizing. attracts the armature 99, which presses the spring 30 into engagement with spring 29, thereby closing an energizing circuit through the pull-in winding 24. This circuit extends from ground G through springs 29 and 30, windings 24 and 27 of the magnet 23 to the bat-Y tery lead 98, thence through the battery B to ground G. The winding 24, upon energizing, attracts the cut-oil' armature 31 and the plunger arm 14. The cut-olf armature, in its energized position, separates the springs 93 and 95 from the springs 29 and 94, respectively, thus opening the circuit through the line winding 25. The armature 99, however, does not fall back immediately upon the opening of the circuit through the winding 28 because the winding 27 is included in the circuit of the pullin winding 24 and holds the armature 99 in an operated position, thereby maintaining the circuit through the pull-in winding 21. The armature 31 also separates springs 96 and 97, thereby disconnecting the bank springs 19 and 21 from cach other. Vhen the plunger arm 14 is attracted it forces the plunger in the bank, pressing the bunk springs 15, 16, 17, 18, 19, 20, 21 and 2:2 into engagement in pairs. The plunger arm, in its attracted position` also closes a contact between springs 100 and 101. The engagement of the bank springs 15 and 17 with thesprings 16 and 18, respectively, furnishes an energizing circuit for the relays 102 and 103. This circuit extends from ground Gr2 through relay 102, bank springs 18 and 17 to line conductor l1, thence through the substation A and back over line conductor 10, bank springs 15 and 16 to and through relay 103 to the battery lead 98, thence through battery B to ground The relay 102. upon energizing. separates the springs 10i and 105 to maintain the circuit of the ringer relay open. The closure of springs 106 and 107 of the relay 103 furnishes an energizing circuit for the cut-ofi' winding 25 of the line switch C. This circuit extends from ground Gr3 through springs 106, 107, 22 and 21 and winding 25 to the batterv lead 98, thence through the battery to ground G. The winding 25 thereupon `energizes to hold the cut-oli' armature 31 and plunger arm 14 in their attracted positions after the winding 21 is (lenergized. The closure of contact between springs 100 and 101 short-circuits the winding 27 of the magnet 23. This short-circuiting of the winding 27 allows the armature 99 to fall back, thus opening the circuit of the pull-in winding 2+ at a point between the springs 29 and 30. The engagement of bank springs 19 and 20 has no effect at this time. The closure of springs 106 and 107 of the relay 103, formerly mentioned, also closes an energizing circuit for the busy trunk relay 39 of the master switch D and the relay 108 (Fig. 2), and also supplies a guarding potential to the contact 109 of the auxiliary master switch bank M and to the closes a circuit extending from ground Gr*- through springs 111 and 112 and motor magnet relay 38 to the battery lead 98, thence through the battery B to ground G. The relay 38 energizes upon the completion of this circuit, withdraws the pin 41 (Fig. 3)

-then through the battery from the hole in the spacing cam 40 in which it is resting and closes an energizing circuit for the motor magnet 32. This circuit extends from ground (ir5 through the motor magnet '32, interrupter springs 113 and relay springs 114 and 42'* to the battery lead 98, B to ground G. The motor magnet 32, being provided with the interrupter sp1-ings 113, begins to operate, in a manner similar to that in which a buzzer operates, to rotate the ratchet wheel 33 and consequently the plunger shaft 34 and all idle plungers that are in locked engagement with it. The motor magnetwill continue to operate until the next opening in the spacing cam has been carried beneath the pin 41, by which time the wiper 37 will have been carried off the grounded contact 110, allowing the relays 39, and 38 to denergize. Thus the pin 41 will drop into the next opening of the spacing cani 40 and open the circuit of the motor magnet relay. If the next trunk after the one seized by the switch C is busy, however, the wiper 37 finds the correspending segment a grounded, the relays 39 and 38 cannot denergize and the master switch will continue to operate until the wiper nds a non-grounded contact, so that the plungers of the idle line switches C will come to rest opposite the vbank terminals of an idle trunk. As long asthe pin 41 is not resting in one of the openings of the spacing cam the contact point 115 is out of engage@ ment with the spring 42, thus cutting o battery from the line windin s of the line switches C, so that no switch can be operated while its plunger is in motion.

The circuit which the relay 103 (Fig. 1') closes through the relay 108 (Fig. 2) extends from ground G through springs 106 and 107, springs 117 and 116, conductor 118 and relay 108 to the battery lead 98. thence through the battery B to ground G. The relay 108. upon energizing, closes a circuit extending from ground G5 through springs 120 and 121, 122 and 123 to trunk conductor 124, thence through springs 126 and 127 of the key K' and through the relay 130 and battery B2 to ground G. The relay 130, upon energizing, closes a circuit from ground G through the signal lamp 131L` and battery B2 to ground G to signal the operator. Upon receiving the signal the operator throws the key K' to separate springs 126 and 127 and close contact between springs 126 and 131, 128 and 132, whereby 'the operators set Q, is bridged across the trunk conductors 125 and 124. The plunger of thc liuc switch l was moved away from the terminals of the trunk conductors 133 and 134 when the line switch C seized the switch E, so that the plunger of the switch H must be brought back to its former position before it is tripped in. When the opcrators set is bridged across the trunk conductors an energizing circuit is established for the line winding 135 of the line switch H. This circuit extends from ground G5 through springs 120 and 121, springs 122 and 123, trunk conductor 124, springs 126 and 131 of key K', through the calling device 87, secondary winding of the induction coil 86 and receiver 85 of the operators set Q, through springs 132 and 128 of key K', conductor 125, springs 136 and 137 and winding 135 to the battery lead 98, thence thmugh the battery B to ground G. The winding 135. upon energizing, attracts the armature 138 to bring the spring 139 into engagement with the spring 122, thereby closing an energizing circuit for the master switch relay 38. This circuit extends from ground .G59 through springs 120, 121, 122, 139, 139 and 140, conductor 142 and relay 38 to battery lead 98, thence through battery B to ground G. The relay 38, upon energizing, closes the circuit through the motor magnet 32 as before, and the master switch D begins to operate. The master switch D will continue to rotate until the wiper 143 of the auxiliary master switch bank M' strikes the Contact 109 which, as has been explained, is supplied with a guarding potential from the connector. Vhen the wiper 143 strikes the contact 109 the relay 144 is energized to open the circuit of the master switch relay 38 and energize the pullin winding 145 of the line switch H. The energizing circuit of the relay 144 extends from ground G (Fig. 1) through the springs 106 and 107, 1,16 and 117, conductor 118, Contact 109, wiper 143, common segment 146 and relay 14+ to the battery lead 98, thence through the battery B to ground G. The relay 144, upon energizing, shifts the spring 139 out of engagement with spring 140 and into engagement with spring 141. The engagement of the springs 139 and 141 provides an energizing circuit for the pull-in winding 145 extending from ground G5 through springs 120 and 121, 122 and 139, 139 and 141, windings 145 and 147 to the battery lead 98, thence through the battery B to ground G. The disengagement of springs 139 and 140 opens the circuit of the motor magnet relay 38, but the said relay 38 does not denergize 'because the wiper 37 is at that time passing over the contact 1,10, which is supplied with a guarding potential,

' as explained Vin connection with the operation of the line switch C. The cncrgization of the winding 145 of the line switch H occurs just as its plunger is passing in front of the bank containing the terminals of the trunk conductors 133 and 1254. The plunger is thrust into this bank. forcing the springs 148 and 150 into engagement with the springs 149 and 151, respectively', and thereby extending the trunk conductors 125 and 124 through to the conductors 133 and 1511. The plunger also closes the contact between springs 152 and 153, thereby short-circuiting the winding 147, which allows the armature 138 to fa'll back and open the circuit of the pull-in winding 145. It is understood, of course, that the cut-olf armature `154 pulls up as soon as the winding 145 is energized, and opens the circuit of the line winding 135 in the same manner as explained for the switch Y C. As soon as the trunk conductors 124 and 125 are connected with the conductors 134 and 133 an energizing circuit is closed through the slow acting relay 156 of the line switch H and the relavs 51 and of the connector E. The relay 156, upon energizing. supplies an energizing circuit from ground (i1 through springs 158 and 159, through the cut-olf winding 157 to the battery lead 98, thence through the battery B to ground G. IThe winding 157 serves to hold the plunger in the bank after the pull-in winding 145 has denergized. The relays 51 and 52 are unctionless at this time and their action willbe explained later in connection with the connector E. The energizing circuit of the relays 156, 51 and 52 extends from ground G through relay 52, conductor 133, springs 149 and 118, trunk conductor 125. through the operators telephone set to trunk conductor 124'and through relay 156, springs 150 and 151. conductor 134 and relay 51 to the battery lead 98, thence through battery B to ground G.

The operators telephone set is now connected with the substation A through' the cond-ensers 62 and 63, and the operator may ascertain the number of the substation desired. O n learning that the substation A of the main exchange is wanted the operator asks the calling subscriber to give his number and then to hang up the receiver and she then restores the key K' to normal position. lVhen the key K is restored the opcrators telephone set is disconnected from the trunk conductors and the circuit of the relay 156 is broken. The relay 156 then denergizes to open the circuit of the cut-off winding 157 of the line switch H. lvhen the winding 157 denergizes the plunger of the line switch H restores to normal position and leaves the operators trunk 124-125 free for another call. 'The plunger of the line switch H, be-

ing self-alining, immediately resumes a po sition in locked engagement with the plunger shaft. When the subscriber at substation A hangs up the receiver the energizing circuit of the relays 103 and 102 is opened at a point between the switch hook 5 and the contact point 9. The relay 103, upon dcnergizing, permits the springs 106 and 107 to separate, thusl opening the holding circuit of the winding 25 of the line switch C and removes the guarding potential from the master switch bank contact 110. The line switch C restores to normal position, leaving the connector switch E free for a local connection. The operator now inserts the plug p2 into the jack J2 and signals the called sub station A by throwing the key K* to bring the springs 160 and 161 into engagement with the springs 162 and 163, respectively. This cuts oil' the line and bridges the ringer generator across the line of the substation A. After ringing the substation A the key K* is restored to norma] position. Then the subscriber at substation A removes his receiver from the hook that substation is supplied with talking battery current over a. circuit extending from ground G" through the relay 77, springs 164 and 160 of key K, tip of-plug p2 and jack J2, line conductor 119, through the transmitter 89, receiver 88 and switch hook 92 of substation A', line conductor 129, through the sleeve of the jack J2 and plug p2, springs 161 and 165 of key K and relay 79 to battery B', thence to ground G. Since the relays 77 and 7 9 bot-h carry current the armature 166n remains in normal position, thus maintaining the circuit of the supervisory lamp 80 open. The operator now inserts the plug P' into the jack J', throws the key K2 to bring the springs 166 and 167 into contact with the springs 168 and 169, respectively, and calls the subscriber A by means of the connector F. lVhen the plug P is inserted into the jack J and the key Kz is thrown, as described, an energizing circuit is completed from ground G through springs 169 and 167, receiver 85, secondary winding of the induction coil 86, calling dev-ice 87, springs 168 and 166, tip conductors of plug` P' and jack J', trunk conductor 170, side switch Wiper 172 and-relay 71 to the battery lead 98, thence through the battery B to ground G. The relay 71, upon energizing, shifts siring 173 out of engagement with spring 1174 and into engagement with spring- 175, whereby an energizing circuit 1s closed through the slow acting release relay 72. This circuit extends from ground G through springs 173 and 175 and through relay 72 to the battery lead 98, thence through battery B to ground (lr. The shifting oispring 176 of the relay 72 disconnects the release magnet 7() from the spring 17 4 of the relay 71 and connects said spring 171 with the vertical magnet 67 preparatory for im ulses. When the operator operates the cal ing device 87 for the first digit 4 the circuit of the relay 71 is opened four times. Each time this circuit is opened the relay 71 denergizes, permitting the spilling 173 to again engage the spring 174. e engagement of the said springs 173 and 174 closes an energizing` circuit through the slow acting private ma et relay 73 and the vertical magnet 67 his circuit extends from ground G through springs 173 and 174, sprin 176 and 177, relay- 73, vertical magnet gsand side switch wiper 178 to battery lead 98, thence through battery B to round G. The vertical magnet is energize four times over this circuit and operates to raise the shaft wipers 64, 65 and 66 to a position opposite the bank level in which are situated the terminals of the desiredY line #114. The vertical magnet 67 and relay 73 will not energize through the resistance 17 9 when the rela 71 is energized, this resistance being bri ged across the springs 173 and 174 to furnish a high resistance path to ground and thus reduce the spark w en the contact between these springs is broken. The relay 72, being slow'acting, does not have time to denerglze during the time the spring 173 is disengaged from the spring 175 while sendingimpulses. The relay 73, which is ineluded in the circuit of the vertical magnet, is slow acting also, and is energized by the first impulse, but does not have time to denergize until all the impulses for the first digit are completed. The relay 73, upon energizing, closes an energizing circuit for the private manet 69. This circuit extends from ground 2 through springs 180 and 181, and through the private magnet 69 to the battery lead 98, thence through the bats tery B toV ground Gr. After the impulses for the first digit are completed-the relay 71 remains in its energized position, thus main'- taining the circuit of the relay 73 open long enough for the said relay to fall back. 'hen the relay 73 denergizes it opens the circuit through the private magnet. 69, which magnet in turn t energizes to release the side side switchwiper 178, in second position, places the relay 71 in control of the rotary magnet 68 instead of the vertical magnet 67 as was formerly the case. Then the calling device is now operated for the second digit 4 the relay 71 operates in the same manner as when the first digit was called. This time, however, the engagement of springs 173` and 174 closes an energizing circuit through the private magnet relay 73 and rotaryu magnet 68. This circuit extends from ground G through springs 173 and 174, 176 and 177, relay 73, rotary magnet 68, contact 185 and side'switch wiper 178 to battery lead 98, thence through the battery A third position cuts switch to second position. The

operates to place the wipers 64, 65 and 66 on the contacts of the desired lineV 44. The relay 73 in this case, as before, energizcs on the first impulse and deiinergizes after the the last one, thus causing the energization and deinergization of the private magnet 69. The operation of the private magnet this time releases the side switch to third position. The side switch wiper 183, in third position, extends the trunk conductor 171 through to the line conductor 11. The movement of the side switch wiper 172 to the trunk conductor 170 through to the line conductor 1() of the substation A, and also disconnects the relay 71 from the conductor 170. The relay 71 now denergizes and the holding .ground for the release relay 72 is transferredrom ground und G in the following manner: W'hen t e side switch wiper 181 reaches the third position a circuit is established from ground G1* through the side switch wiper 184, springs 186, 187, 188 and relay 189 to the conductor 193, thence through the side switch wiper 183, trunk conductor 171, sleeve of the plu P' and jack J and relay 78 to battery B and thence to ground G. The relay 189 energizcs upon the establishment of this circuit and operates to close the Contact between the springs 190 and 191. The engagement of the springs 190 and 191 closes a new holding circuit for the relay 72 extending from ground G through the said 100 springs 191 and 190 and relay 72 to the battery lead 98, thence through battery B to ground The side switch wiper 184. in

third position, also supplies a guarding potential from ground G1* through the pri- 105 vate wiper 66 to all the private bank contacts of the line #-14 to protect. it from seizure by any other connector and the said side switch wiper 184 also provides an energizing circuit for the cut-cti' winding of the 110 line switch C. This circuit extends from ground (ilihrough side switch wiper 184,

shaft wiper 66. private bank contact 74,

conductor 192 and bridge-cut-ofi' winding 25') to :the battery lead 98, thence through the 115 battery l5 to ground (i. The winding 25,

upon being* energized, attracts the arma ture 31, which separates the springs 93, 95

and 97 from the springs 29, 9-1 and 96, resl'lectively, thus cutting ofi the line windinor 120 28 from the line #44, so that the switch will not be operated when the receiver at substation A is again removed from the hook. The winding 25 is not strong enough to pull down the plunger arm 14 when said 125 arm is in normal position. Then the connection is thus extended to the line #44 the operator restores the key K* to normal po sition and then she may signal the substation #4:4 by operating the key K to place 130 the springs 191 and 195 in contact with the sprin 196 and 197, respectively. W'ith the key K3 in this position the cord circuit is cut olf from the line and the ringer generator L is bridged across the line of substation #44. A circuit. now extends from ground through the ringer generator L', trunk conductor 170, line conductor 10, through the condenser 8 and ringer 7 of substation A, and back over line conduc tor 11, trunk conductor 171. through springs 195 and 197 to the battery B' and to ground whereby the ringer 7 willbe operated to notify the subscriber at substation A that his connection has been completed. The engagement of the springs 195 and 197 of the key K also furnishes a battery conncction for maintaining the holding circuit of the relay 189 of the connector F while the key is operated. After signalingV the substation A the key Ks is returned to normal position, and as soon as the called subscriber removes his receiver the substation A is provided with talking battery current from ground G9 through the relay 76, over the trunk conductor 170 and line conductor 10, transmitter 6 and receiver 4'of the substation/A, back over the line conductor 11 and trunk conductor 171, through the supervisory relay 78 and battery B' to ground G.

'hen the receiver at the called substation A is restored to the hook upon the completion of the conversation, the circuit through the supervisory relays 77 and 79 is broken, but the relay 79 is energized over a circuit extending from ground (l:15 through the relay 196, sleeve conductor of the jack J2, thence to the sleeve conductor of the plug p2 and through the relay 79 to the battery B. Since the amature 166 is now attracted by the relay 79 alone it is brought into contact with the contact point 167, thereby establishing an energizing circuit from ground G through the lamp- 80. Likewise, when the receiver at the substation A is restored to the switch hook the Ielav 78 remains energized over a circuit extending from ground G1 through coil 197,

sleeve of jack J and sleeve of plug P', through relay 78 to the battery B'. The rclay 78 attracts the armature 198 against the contact point 199, thereby closing an energizng circuit through the supervisory lampV 81. The simultaneous glowing of the lamps 80 and 81 signifies to the operator that the conversation is completed and she may take down the connection. The release of the switch F is initiated by the removal of the plug l" from the jack J in the following manner: It will be seen that the holding circuitffof the relay 189 is broken when thev said plug P' is removed from the jack J. The relay 189 thereupon denergizes and permits the springs 190 and 191 to separate, thus opening the holding circuit of the release relay 72. The slow acting relay 72 in turn denergizes and permits the springs 176 and 200 to engage. Thus an energizing circuit is closed through the release magnet 70, said circuit extending from ground G through springs 173 and 174, springs 176 and 200, release magnet 70, normal springs 201 and 202 (which were closed when the shaft was raised the first step) to tlnl batteryV lead 98, thence through tlwbattcry B to ground (i. The release magnet cnergizes and restores the connector l" to normal position. Then the switch shaft returns to its normal position it separates the springs :01 and 202, thus leaving the release magnet normally denergized.

Returning now to that part of the operation when the wipers of the connector F had reached the line of substation A. but before the side switch has moved to third positionsuppose that the line #41 were busy. In this case the wiper 66 finds a guarding potential present at the private contact 74 or 75, said potential being supplied by some other switch E or F which has made connection with the line, or by the individual switch C of the line if it is a calling line. 1fv the private wiper 66 does find a guarding potential present at the private contact 74 the energizing circuit of the private magnet 69 is maintained after the relay 73 falls back on thc cessation of the impulses for the second digit. The energizing circuit for the private magnet now extends from' the grounded contact 74 through side switch wiper 184 (bearing in mind that the side switch -is still in second position), through springs 203 and 204, rela)r :205, springs 182 and 181 and private magnet 69 to the battery lead 98, thence through the battery B to ground G. vThe spring 181 is so adjusted that it engages spring 182 before-leaving spring 180, thus preventing the denergization of the private magnet while its holding circuit is being shifted. The rclay 205 is also included in this new circuit through the private magnet 69 and it now energizes. When the relay 205 energizes it shifts spring 204 out of engagement with spring 203 and into engagement with spring 200, whereby the relay 205 and private magnet 69 are disconnected from the grounded contact 74, but at the same time supplied with a holding ground from ground G" through the springs 209 and '210 and springs 206 and 204. The side Switch is now locked in second position and the busy signaling machineis connected to the trunk conductor 171 through the springs 207 and 208 and side switch wiper 183. The connector F is released from this osition also by the removal ofthe plug from the jack J. In this case the circuit of the slow acting rethe subscriber secures connection with theoperator vin the same manner as before explained. Vhen the subscriber removes his receiver from the switch hook the line switch trips in to extend the line conductors 10 and 11 to a connector E, and a signal lamp 131 is lighted at the main exchange. The key K' is then thrown to bridge the opcrators set across the trunk conductors 121 and 125, and the line switch H operates to connect the conductors 1'21 and 125 with the Sallie switch E to which the line of the substation A has been extended by the line switch C. Upon learning thatr a. subscriber of the branch exchange is desired the operator simply .operates the calling device 87 to cause the switch E to bring the line Wipers 43 and 44 into connection with the desired lille. It will be remembered that when the line switch H extends the conductors 1% and 125 to the connector E the relays 51 and 52 of the eonnector E are energized as well as the relay 156 of the line switch H. The relay 51. upon energizing, presses the springs 211. 212 and 213 into engagement, thereby supplying ground to the spring 214 and establishing an energizing` circuit for the slow acting release rela-y 59. This circuit extends from ground Gr18 through the springs 211 and 212 and relay 59 to the battery lead 98, thence through battery B to ground G. The relay 52. in its energized position, maintains the circuit of the ringer relay 60 open. 'hen the release relay 59 energizes it shifts the spring 216 out of engagement with the spring 218 and into engagement with the spring 217, thereby disconnecting the spring 219 of the relay 51 from the release magnet 56 and connecting it with the vertical magnet 53,

W'hen the calling device is operated for the first digit the circuit of the relays 5l and 52 is opened'a certain number of times corresponding to the digit called. The relay 15G, (Fi 2). being slow act-ing. remains energize( while the impulses are being transmitted. llacli time the relay 51 denergizes an energizing circuit is closed through the vertical magnet and slow actiner relay This circuit extends from ground (11s through the springs 211 and 219, 216 and 217, relay 55, side switch wiper 49 and vertical magnet 53 to the battery lead 9S. thence through hat tery B to ground (l. The magnet 53 energizes each time the circuit is closed and operates to raise the shaft wipers Step by step to a position opposite the bank level con taining the terminals of the desired line. As soon as the shaft is raised the Erst Step the normal springs 57, 57 and 58 engage, thereby supplying battery current to the release magnet 56, private magnet 50 and ringer relayV (i0. The, slow acting relay 55, which is included in the circuit just traced throu h the vertical magnet 53, energizes upon t e first impulse and remains so until the iinpulses are completed, when it resumes its normal position. When the relay energizes it closes an energizing circuit through the private magnet 50. This circuit extends from ground G through-the springs 220 and 221, private magnet 50, normal springs 57 and 58 to the battery lead 98, thence through battery B to ground G. The private magnet. upon energizing and denergizing, trips the side switch to second position, whereby the rotary magnet 5-1 is brought under the control of the relay 51. "hen the calling device is now operated for the second digit the rotary magnet 54 is actuated to rotate the shaft wipers 43 and 14 onto the terminals of the desired line in the same manner that the vertical magnet 53 was operated to raise the said wipers to the proper bank level. The relay 55 operates the same for the second digit as-for the first. and causes the private magnet to release the side switch to the third position. The callinar dcvice is now operated once. to send at least one. impulse to the connector E. This time, when .the relay 51 denergizes, a. circuit is established through the relay 222 from ground G1 through springs 211, 219, 216 and 21T. relay 55, side switch wiper 49, con-` 100 tact 223 and relay 222 to battery lead 98, thence through the battery B to ground G. The relay 222, upon energizing, locks itself over a circuit extending from ground G3 through sprinrs 106 and 10T, springs 11T 105 and 224 and re ay 222 to the battery lead 98, thence through the battery B to ground G. The relay 222, in its energized position. also removes the guarding potential from the auxiliary master switch bank M and closes 110 a circuit for the release relay 59. This circuit extends from the ground G3 to the spring 117` as formerly traced, thence through spring 225 and relay 59 to the battery lead 98, thence through the battery B to 115 ground (l. This circuit is provided t'or holding the release relay energized in case the operator releases the line switch H before the, called subscriber answers. thereby allowing the relay 51 to denergize and open 120 the circuit of the relay 59 at a point between the springs 211 and 212. The relay 222, in its energized position, also furnishes a guarding potential from ground G through springs 106, 10T, 117 and 224. bank springs 125 2O and 19 to the private normal conductor 193, and thence to the upper private bank contacts of the calling line.

The relay 222 While energized renders the signal 131 at the operators position inop- 130 erative by opening the springs 116 and 117 in the circuit. of relay 108, which relay controls said signal so that if the operator should release the key K', the said signal 131 will not again be displayed.

Thus it' is seen that the guarding potential is not supplied to the calling line until after the side. switch has passed to third position. 'lhis arrangement is provided so that itV will be possible to call hack onto the line of the calling subscriber and give him connection with another subscriber on the same line. The called line is provided with a guarding potential by the side switch wiper 4S as soon as it reaches third position.

After the connection has been completed and theloperatorls key K is restored the calling subscriber may signal the called substation by pressing the push button 2, whereby the resistance 3 is inserted in the circuit of the relays 102 and 103. These relays are so adjusted that when the resistance 3 is included in their circuit lthe relay 103 remains energized and relay 102 falls back. ll'hcn the relay 102 falls back anA energizing cir cuit is closed through the ringer relay (S0. This circuit extends from ground G'" through springs 106, 10T, 105, 104. 214 and 215, relay (i0 and normal springs 5T and 58 to the battery lead 08. thence through the battery B to ground G. The ringer relay 60, upon energizing, opens the line connection at a point between springs 220 and 22T andconnects the ringing generator L to the called line. The circuit, of the ringing current extends from ground through the generator L and through springs 228 and 226, side switch wiper 46, shaft wiper 13, thence over the line to the called substation and back over shaft wiper 44. side switch wiper 47, ringer relay springs :325i and E230 and condenser 61 to ground (12. lt will be seen that with this arrangement, when the calling subscriber is ringing back to another substation on his own line, the relay 102 is shuntcd by the condenser 01 and therefore will not be energized by the ringing current. If so desired the operator may ring the called substation by groumling both sides of the trunk. In this case the relay 51 remains energized while the relay 52 falls back, thus energizing the ringer relay over'a circuit extending from ground G through relay springs 211. 213, 214 and 215 and through the ringer relay 60 to the battery lead 98, thence through the battery ll to ground G. As soon as the connection is completed the operator`s key K is restored to normal position. whereupon the relay 150 denergizes to initiate the release of the line switch H and free the trunk 124, 125 in the saine manner as previously described. The called substation is supplied with talking battery current from ground G through relay o2, side switch wiper 47,4v shaft wiper +1,

thence through the substation apparatus and back over shaft wiper 13, side switch wiper' 46, ringer relay springs 220 and 227 and rclay 51 to the battery lead 98, thence through battery B to ground G.

lf the subscriber at substation A hangs up his receiver first; upon the termination ot' the connection. the relays 103 and 102 bccome deinergized. The separation of the springs of the relay 103 disconnects one ground connection G3 from the cut-ott' winding 25 of the line switch C, but the relay 22; is still held up by the ground G and maintains a connection between ground G18 and eut-olf winding 25 of the line switch C. Now, when the called subscriber hangs up his receiver the relays 51 and 52 denergize, thus disconnecting the ground GS from the relays 222 and 59 and the cut-oil' winding E25 of the line switch C. W'hen the ground is cutoff from the cut-oil winding 25 the plunger of the line switch is withdrawn from the bank and the substation A is disconnected from the connector l". The removal of the ground connection from the rclay 59 of the connector E allows this relay to denergize and close an energizing circuit through tie release magnet 50. The circuit through the release magnet 5G extends from ground G through relay springs 211, 219, 316 and 218, niagnet 56, normal springs 5T and 58 to battery lead 08, thence through the battery B t'o ground G. The release magnet 56. upon energizing, restores the 100 connector E to normal position. As soon as the switch shaft reaches its normal position it opens the normal springs 57 and 5S, thereby cutting battery ott' of the release magnet 56 and allowing it to decnergize.

It' the called subscriber restores his receiver to the switch hook first the relays 51 and 52 dcnergize, but the relays 22:2 and .30 are still supplied with ground from ground (i3 by the relay 103. 1n this case the ground 110 is cut ott' of the. relays 222 and 59 when the receiver at the calling substation is hung up and the relay 103 allowed to denergize. The connector land line switch (l release. in the same manner as before explained, 115 upon the de'energization of the relays 22;! and 59.

lf the called liuc is busy when called by the connector-VE the private magnet does not denergize when the relay 55 falls back after 120 the last digit is called. but remains energized and locks the side switch in second position and the calling subscriber receives the busy signal in a manner similar to that described for the connector F. The locking circuit 125 for the private magnet 50 of the connector E after the relay 55 falls back extends from the grounded upper private bank contact of the busy line. through shaft wiper 15, side switch wiper -18 (in second position), springs 130 221* and 221 (spring 221 engages spring 221-before it disengages s ring 220), private magnet 50 and norma springs 57 and 58 to battery lead 98. The busy signal circuit extends from the secondary winding ot' theV busy signaling machine I through springs 231 and 232, condenser 63. bank springs 18 and 1T, line conductor 11, through the substation A, line 10, springs 15 and 16, relay 103, battery lead 98 and thence to the other terminal of the busy signaling machine I. The primary circuitl of the busv machine extends from ground G2* through the interrupter 233 and primary 'winding 2i# to battery lead 18.

It. will be seen that it requires a guarding ground upon the upper private bank contact of a busy line to prevent a connector ll from obtainlng connection with that line, and when connection is extended from a calling line through the connector E this guarding ground ihr the calling line is not provided until the side switch of the connector has passed to third position. Thus it is possible for the connector E to call back on the calling line to signal some other subscriber thereon in case it is a party line. In case the called subscriber is not on the same line as the callingsubscriber the side switch wiper 48. in third position, furnishes a guarding potential through the upper private wiper 45 to the upper private bank contacts of the called line, while theside switch wiper 4S, in' third position, furnishes a ground through the lower private wiper 45* to energize the cut-off winding of the called subscribers line switch C.

In the general arrangement of the system shown in Fig. -t there are represented two branch exchanges equipped with substations A, line switches and H and connectors E and F similar to those shown in Figs. 1 and 2. There is also shown a group of main exchange substations A connected to a mauual board N. Two operators )ositions of this board N are represented. ne position is an ordinary position, where connections between" main exchange subscribers are made. The other position is a so-called trucking position-that is, a position where connections are made between diti'erent. branch exchanges and between branch exchange substations and main exchange substations. T he usual order wire between the regular operator-s position `and the trunkmg position is represented at R. Besides the apparatus described, there may also be connected with the manual board N at'ull au tomatic exchange similar to that disclosed in British Patent No. :6,301 of 1906. and represented herein at T. This automatic exchange comprises substations T. line switches T2, first selector switches T3` second selectors '1" and connectors T". From some of the bank contacts of the rst selectors T3 trunk lines lead to the trunking position of the board N, where they terminate in jacks J7 (Fig. 7). Leading from the board N are trunk lines which lead from jacks J (Fig. 5) to rst selectors T3, through the medium of which access may be had to any substation in the automatic exchange. In Fig. 6 there is shown a cord circuit which is suitable for extending connection from any line in the manual exchange to the automatic exchange T. The left-hand end ot' this cord is the same as the left-hand end of the cord 0 (Fig. 2). while the right-hand end is provided with a supervisory relay bridged across the talking circuit and with a key K by lne-ans of which a calling device of the pro Jer character for controlling the switches o the automatic exchange 'l may be connected with the cord. Calls coming in from the automatic exchange may Vbe answered with thc cord O (Fig. 2).

- From the foregoing it will be seen that I provide an operators equipment, and means for automatically directing the calls to said equipment, whereby the operator may answer the call and extend the same to the line of the called subscriber. The trunking connection from the manual board to the trunk between the line switch and the connector is not included in the calling connection when one subscriber calls another at the distant exchange, and is released by the operator without disturbing the calling connection. In this way the same trunk and manual lequipmentl can be used for successively answering calls, and for extending each call in the desired direction, the trunk not being an essential part of any calling connection, but being used merely as a means for enabling vthe opera-tor to control the automatic switches that are provided for connecting calling lines with called lines at the branch or distant exchange. It follows, therefore, that no operator 'is necessary at the said branch exchange, and that the operator at the main exchange will answer all calls for the distant exchange, and then complete the same to the called lines. When the subscribers at the branch exchange hang up their receivers the automatic connections are released and restored to normal condition.

It will also be seen that I provide an improved connector for use in making reverting calls on party lines, the said connector heilig provided with a plurality of private wipers and means for grounding cach private wiper when the 51de switch passes to third position. Thus one private wiper is used for closing an energizing circuit through the bridge cut-off relay coil of the called line. and the other private wiper is used for establishing a guarding potential for the party line, or for closing a circuit to automatically prevent the completion of the connection if the called line is busy.

llt)

I do not. limit myself to the exact construction shown and described.

'hat I claim as my invention is l. In a telephone system, a line, a nonnumerical switch for said line, Va. numerical switch, a trunk leading to said numerical switch adapted to be seized by said nonnumerical switch, another trunk, and means for controlling said numerical switch over two sides of both of said trunks in seriesto extend a talking circuit connection from said line through said switch, which connection excludes one of said trunks. Y

2. In a telephone system, a calling line, a called line, automatic switching means for connect-ing the two lines together, a manual board, a trunk line leading from Asaid board, an operators telephone, a manual switch for connecting the telephone with the trunk, an automatic switch for connecting the trunk and calling line, and means for then controlling said automatic switching means over the two sides of said trunk in series and through said automatic switch.

3. In a telephone system, a. connector provided with line wipers, a pair of auxiliary wipers working simultaneously with the line wipers, means for closing a busy test circuit through one auxiliary wiper, a. line, a relay for said line, and means for closing an energizing circuit for said relay through the other auxiliary wiper.

4. In a telephone system, a party line, another line, and a connector for enabling one party-line subscriber-to call another on the same line, orion the other line, saidV connector provided with a plurality of wipers, a three-position side switch adapted to ground two of said wipers by movement to the third position, a busy test circuit closed through one of said wipers while the side switch is in second position, a guarding potential connection adapted to be closed by the same wiper when the side switch is in third positlon, a relay for each line,I and circuits for said relays controlled by the other of said wipers while the side switch is in third position.

In a telephone system, aline a switch. a. trunk line, means for controlling said switch over the twoA sides of said trunk line in series to extend a talking circuit connection from said line through said switch, which connection excludes the said trunk, and means for releasing said excluded trunk alone.

6. In a telephone system, an automatic switch, a trunk line, means for controlling said switch over the two sides of said trunk line in series to extend a talking circuit connection through said switch, which connection excludes said trunk, and meansfor releasing said excluded trunk alone.

7. In a telephone system, a calling line` a called line, automatic Switching means for connecting the two lines together, a manual board, a trunk line leading from said board` an operator`s telephone. a manual switch for wnnecting the telephone with the trunk, an automatic switch for connecting the trunk and calling line, means for then cont-rolling said automatic switching means over the two sides of said trunk line in series and 'through said automatic switch, and means for releasingr the. trunk alone.

8. In a telephone system, a connector provided with line wipers, a pair of auxiliary wipers working simultaneously with the line wipers, means for closing a busy test circuit through one auxiliary wiper, a line.y a relay for said linemeans for closing an energizing circuit for said relay through the other auxiliary wiper, a manual board connection by which an operator controls said connector` and means for releasing said manual board connection alone.

9'. In a telephone system` a party line, another ]ine, a connector for enabling one party-line subscriber to call another on the same line, or on the other line, said connector provided with a plurality ofwipers, a threeposition side switch adapted to ground two of said wipers by movement to the. third position, a busy test circuit closed through one of said wipers while the side switch is in second position. a guarding potential connection adapted to he closed by the same wiper when the side switch is in third position, a relay for each. line, circuits for said relays controlled hy the other of said wipers while the side switch is in third position` a manual board connection by which an operator controls said connector, and means for releasing said manual board connection alone'.

10. In a telephone system, a line, a nonnumerical switch for said line` a numerical switch. a trunk line leading to said numerical switch adapted to be seized by said nonnumerical switch` another trunk line.` means for controlling said numerical switch over the two sides of said last trunk line in series and a portion of the first trunk to extend a calling connection from said line. which con nection excludes one of said trunks, and means for finding said line when called.

11.v In a telephone system` a calling line, a called line, automatic switching means for connecting the. two lines together, a manual board, a truuk line leading from said hoard, an operator`s teleplmne. a manual switch for connecting the telephone with the trunk, an automatic switch for connecting the trunk and calling line, meansv for then controlling said automatic switching means over the two sides of said trunk line in series and through said automatic switch. and means for finding the calling line when used as a called line.

12. In a telephone system, a connector provided With line wipers, a pair of auxiliary v soA wipers working simultaneously with the line wipers, means for closing a busy test circuit throu h one auxiliary wiper, aline, a relay qfor sai line, means for closing an energizing circuit for said relay through the other auxiliary wiper, and subscriber-controlled means for releasing said connector by opening the line at the calling substation.

13. In a telephone system, a party line, another line, a connector for enabling one party-line subscriber to call another on the same line, or on the other line, said connector provided with a plurality of wipers, a. three-position side switch adapted to ground two of said wipers by movement to the third position. a busy test circuit closed through one of said wipers while the side switch is in Asecond position, a guarding,r potential connection adapted to be closed by the same wiper when the side switch is in third position, a relay for each line, circuits for said relays controlled by the other of said wipers while the side switch is in third position, and Subscriber-controlled means for releasing said connector by opening the line at the calling substation.

14. In a telephone system, a line, a nonnumerical switch for said line, a numerical switch, a trunk leading to said numerical switch adapted to be seized by said nonnumerical switch, another trunk, and means for. controlling said numerical switch over the two sides of said trunks in series to extend a calling connection from said line, which connection excludes one of said trunks.

15. In a telephone system, a calling manual line, a called manual line, automatic switching means. an operators line, means for setting up a talking connection over the opera-tors trunk to the calling manual line. and means for controlling said switching means over the two sides of said operators line in series to connect the calling and called lines together, which calling connection excludes the said operators line.

16. In a telephone system, a calling line, a called line. automatic switching means for connecting the two lines together, a manual board. a trunk leading from said board, an operators telephone, a manual switch for connecting the telephone with the trunk, an automatic progressively movable switch for connecting the trunk and calling line to establish a talking circuit with said calling line, and means for then controlling said automatic switching means over the trunk n and through said automatic switch, such control being over the two sides of the talking circuit -ot' the trunk in series.

17. In a telephone system, a plurality of trunks, an operatm"s equipment, means controlled over a calling line for automatically selecting an idle trunk and for extending connection thereto, means for automatically connecting the selected trunk with said equipment to enable the operator to answer the call, and means controlled by the operator over the two sides of said automatic connection in series to extend the call.

18. In a telephone system, an operators position with answering and calling devices, a calling line. means for automatically conneet-ing,r the line with said operators position. and means controlled over the two sides of said automatic connection in series by the operators calling device to extend the call.

19.*In a telephone system, a connector provided with line wipers, a pair of auxiliary wipers working simultaneously with the line wipers, means for closing a. busy test circuit through one auxiliary wiper, a line, a relay for said line, means for closing an energizing circuit for said relay through the other auxiliary wiper, a trunk, and means for controlling said connector over the two sides of said trunk in series.

20. In a telephone system. a party line,

another line, a connector for enabling,r one party-line subscriber to call another on the same line, or on the other line, said connector provided with a plurality of wipers, a three-position side switch adapted to ground two of said wipers by movement to the third position, a busy test circuit closed through one of said wipers while the side switch is in second position, a guarding potential connection adapted to be closed by the same wiper when the side switch is in third position, a relay for each linecircuits for said relays controlled by the other of said wipers while the side switch is in third position, a trunk, and means for controlling said connector over the two sides of said trunk in series.

21. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking connection from said terminal over either of said branches, automatic switches associated with one of said branches, and means for transmittingimpulses back over the two sides of the talking circuit of said other branch in series to operate said automatic switches.

22. In a telephone system, a subscribers line, a trunk line having two branches having acommon trunk terminal, a trunk-selecting switch for said subscribers line for seizing said trunk terminal to extend a talking,r connection from said line over either branch of said trunk, automatic switches as sociatcd with one of said branches. and means for transmitting impulses back over thc two sides of the talking circuit of said other branch in series to operate said switches.

23. In a telephone system, a manual switchboard. an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic. switch, means for seizing said common terminal and for extending a. talking connection over either of said branches, and means for transmitting impulses back over two sides of the talking circuit of said branch extending to said switchboard in series to operate said automatic switch.

24. In a telephone system, a subscribers line` a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch, a nonnumerical trunk-selecting switch for said subscribers line, means includin said switch for seizing said common terminal for extendingr a talking connection over either of said branches, and means for transmitting impulses back over two sides of the talking circuit of said branch extending to the manual switchboard in series to operate said first-mentioned automatic switch.

25. In a telephone system, a manual switchboard, an automatic switch, a trunk iine having two branches having a common terminal. one of said branches leading to said switchboard and the other to said automatic switch. means for seizing said coinmon terminal for extending a. talking connection over either of said branches, a signal at said switchboard, means for displaying' said signal when said trunk is seized, and means for transmitting impulses back over two sides of the talking circuit of said switchboard branch in series to operate said automatic switch.

2G. In a telephone system, a plurality of subscribers lines, a trunk line, a manual switchboard. means for extending a connection from one of said subscribers lines over said trunk to said manual board, means for extending said connection from said board to a second of said subscribers lines, automatic switches for extending a connection to' another of said subscribers lines, and means at said manual board for transmitting impulses back over said trunk to operate said switches.

2T. In a telephone system, a `main exchange. a branch exchange, a trunk line extending from said branch exchange to said main exchange, said trunk line being adapted for use in completing talking connectionsl extending from a subscribers line vin said branch exchange to a subscriber in said main exchange, automatic switches `for completing connections with a called subscribers line in said branch exchange, and means for transmitting impulses back over two sides of said trunk line in series from said main to said branch exchange to operate said switches.

28. In a telephone system, a trunk line having two branches having a common terminal` means for extending a talking connection from said terminal over either of said branches, an automatic switch associated with one of said branches, said switch having 'contact arms normally disconnected from said trunk, means for transmitting impulses back over the two sides of the other branch of said trunk in series to operate'said switch, and means controlled by the operation of said switch for connecting said switch arms with said trunk.

29, In a telephone system. a trunk line having two branches having a common terminal, means for ext-ending a talking connection from said terminal over either of said branches, automatic switches associated with one of said branches, a condenser in said trunk, a relay connected with said trunk on one side of said condenser, means for transmitting impulses back over the two sides of said second branch of said trunk in series to operate said relay, and means controlled by the operation of said relay for controlling the operation of said automatic switches.

30. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal `for extending a connect-ion over either of said branches, a condenser in one side of said trunk, a relay connected with said trunk on one side of said condenser. means at the manual switchboard for transmitting impulses back over two sides of one branch of said trunk in Aseries to operate said relay, and means controlled by the operation of said relay to control the operation of said automatic switch.

31. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal, a relay connected with said trunk. an impulse transmitter at said manual switchboard for transmitting impulses over two sides of saidtrunk in series to intermittently energize said relay, and means controlled by said intermittent cnergizations of said relay to transmit a series of grounded impulses to said automatic switch to control the operation thereof.

32. In a telephone system, a subscribers line, a plurality of trunk lines, a trunkselecting switch adapted to make connection with an idle one of said trunks, cach of said trunks having two branches, a spring jack at the end of one of said branches, an autol matic switch in which the other branch terminates, and means associated with said spring jack for transmitting impulses back over two sides of one brauch in series to-opcrate the automatic switch associated with the other branch of said trunk. In a telephone system, a line, a second line, a signal associated withsaid secondv line, an automatic progressively movable switch for establishing connection between said first. and second lines responsive to a single impulse of current and for thereby operatingr said signal, a third line, an automatic progressively movable switch for said third line. means for operating said switch in response to said signal for extending connection froin said third line to said second line in response to a single impulse of current.

34. In a telephone system, a up of lines1 an automatic switch for eac one of said lines, a second group of lines, signaling means associated with said second group of lines, means for operating any one of said switches for establishing a connection between its line and any one of said second lines in response to a single impulse of current. and for thereby giving a signal to an operator through the instrumentality of said signaling means, another line, an automatic switch for said other line, means for operating said last automatic switch in response to said signal, said switch operable to select said established connection and to connect said other line with said established connection as a result of a single impulse.

3.3. In a telephone system, a plurality of lines, a pair of test circuits for each line. connector switches having access to said lines. means for applying a guarding potential to either of said circuits separately, one of said connectors responsive when the potential is applied to either test circuit, and another responsive when the potential is applied to only one ot' said circuits.

36. ln a telephone system, a line. a pair of test circuits for said line. connector switches having access to said line, means for applying a busy potential to one of said circuits to prevent one of said connectors from establishing a connection with said line and for applying a potential to thc other circuit to prevent all of said connectors from establishing a connection with said line.

37. ln a telephone system. a calling manual line. a called manual line` automatic switching means, an opcrators line. an automatic progressively movable switch for connecting said calling line and said operators line. and means for controlling said switching `means over thel two sides of said operator`s line in series to connect the calling and called lincs together, said last connection cxcluding ,said opcrators line.

3B. In a telephone system, a calling telephone line. a trunk line terminatingr in an 65 .automatic connector switch, an individual liuc switch responsive to the removal of. the ,receiver on thc calling line for extending ermnection to said trunk liuc, a finder switch and a branch of said trunk line accessible. thereto, an opcrators position and a call signal thcreat actuated upon the seizure of said trunk line. means whereby the operator maP initiate the operation of said finder switch to establish connection with said branch, and means whercb)r the operator may then control said connector over a circuit extending through said iinder switch and over a conductor of said branch to complete the connection to a called line.

39. In `a telephone system, a calling telcphone line, a trunk line terminating in an automatic connector switch, an individual line switch responsive to the removal of the receiver on the calling line for extending connection to said trunk line. a finder switch B5 and a branch of said trunk line accessible thereto, an operators position and a call signal thereat actuated upon thc seizure of said trunk line, means whereby the operator mav initiate the operation of said linder switch to establish connection with said branch. means whereby the operator may then control said connector over a circuit. extending through said finder switch and over a conductor of said branch to complet-c thc'connection to a called line, and means for rcleasing said finder switch without intcrfcring with the connection.

40. In a telephone system. subscribers lines. trunk lines. individual line switches for said subscribers lines for connecting with idle trunk lilies. a tinder switch having access to said trunk lines for extending one to which connection has been established to an operators position. and a master switch for controllinglr said line switches and said finder switch.

41. In a telephone system, means for sctting up a talking circuit. between a calling and a called subscribers line. a connector switch for seizing the called line controlled over 'two sides of the. talking circuit in series. means controlled b v the calling subscriber for releasing said switch, and means for preventing a calling subscriber from relcasing said switch.

42. ln a telephone system, a calling and a called line, means including a trunk line and a connector switch for connecting the subscribers on said lines in conversation. said connector being controllable over the two sides of said trunk line. in series, and means for releasing said connector controlled by whichever one of said subscribersI who last replaces his receiver.

43. In a telephone system. a manual switchbmird` an automatic switch, a trunk line having two branches having a common terminal. Said branches normali)r connected to said terminal, one of said branches lead- 130 ing to said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, n relay bridged across Huid trunk ou one side nt? snul condenser, a si 'nal at said Switch-- board controlled hy saut relay, and liu-.uns for transmitting impulses vback over said trunk from said manual switchboard to op crate said automatic switch.

44. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, said branches normally connected to said terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay Vbridged across said trunk on one side of said condenser, a signal at said switchboard controlled by said relay, a second relay connected with said trunk on the other side of said condenser, means at said manual switchboardl for intermittently energizing said second relay, and means controlled by the operation ofsaid second relay for controlling tlie operation of said automatic switch.

45, In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, said branches normally connected to said terminal,one of said branches leading toisaid switchboard and the other to said automatic switch. means for seizing said common terminal for extending a connection over either of said branches, a condenser in one side of said trunk, a relay connected with said trunk on one side of said condensermeans at the manual switchboard for transmitting impulses back over one branch of said trunk to operate said' relay, means controlled by the operation of said relay to control the operation of said automatic switch, whereby a talking circuit is set up over the said common terminal throu h the. medium of said manual swtchboar and lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group.

46. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, said branches normally connected to said terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condenserfa" signal at said switchboard controlled 'by said relay';-means for transmittingV impulses back overs'a'id trunk from ,said manual switchboard to operate said automatic switch, and lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groups and motion in a plane at. right angles thereto to find a line in a selected group. l

47. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, said branches normally connected to said terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condenser, a signal at said switchboard controlled by said relay, a second relay connected'with said trunk on the other side of said condenser, means at said manual switchboard for intermittently energizing said second relay, means controlled by the operation of said second relay for control` ling the operation of said automatic switch, and lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group.

48. In a telephone system. a manual Switchboard, an automatic switch, a trunk line having two branches having a common termina-l, one of -said branches leading to said switchboard andthe other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side ot' said condenser, a signal at said switchboard controlled by said relay, means for transmitting impulses back over said trunk from said manual switchboard to operate said a'utomatic switch, said signal associated with one of the branches, and means under the control of said automatic switch for rendering said signal inoperative over the trunk.

In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condenser, a signal at said switchboard controlled by said relay, a second relay connected with said trunk on the other side of said condenser, means at said manual switchboard for intermittently energizing said second relay, means controlled by the operation of said secondv relay for controlling the operation of said automatic switch, said signalV associated with one of the branches, and means under the control of 'said automatic switch for rendering said signal inoperative over the trunk.

50. In a telephone system, a plurality of subscribers lines, a trunk line having two branches and a common terminal, a manual switchboard, .means for extending a connection from one of said subscribers lines over one branch of said trunk to said manual board, means for extending said connection from .said -board to a second of said slibscrbers lines` an automatic switch in the. other branch for extending said connection from sad lirst subscribers line to another of said subscrilms lines over the common terminaLmeans at said manual board for transmitting impulses back over said trunk to operate said switch. lincs divided into groups; extending from said automatic switch. said switch having motion in one plane. to select 1groups and motion in a plane at right. angles thereto to find a line" in a selected group. a signal associated with one of the branches, and means under the control of the automatic switch in the other branch for rendering said'signal inoperative over the trunk.

51. In a telephone system, a manual switchboard, an automatic switch. a trunk line having two branches having a common terminal, one. of said branches leading to said switclilmard and the other to said automatic switch, means for seizing said common terminal for extending` a connection over either of said branches` a condenser in one side, of said trunk. a relay connected with said trunk on one side of said condenser, means at the. manual switchboard for transmitting impulses back over one lbranch of said trunk to operate said relay. Ameans controlled h v the operation of said relay to control the operation of said automatic switch, whereby a talking circuit is set up over the said commonterminal through the medium ot' said means at said manual switchboard, lines divided into groups extendingr from said automatic switch, said switch having motion in one plane to select groups and motion in n plane at right angles thereto to find a line in a selected group, a signal associated with one of the branches, and means under the control of said automatic switch in the other branch for rendering said signal inoperative over the. trunk.

59.. In a telephone system, a manual switchboard. an auton'iatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch. means for seizing said common terminaba condenser in said trunk` a relay bridged across said trunk on one side of said condenser. a signal at said switchboard controlled by said relay. means for tramanittiingy impulses back over said trunk from said manual switchlmard to operate said automat-ic switch, linesI divided into groups extending from said automatic switch, said switch having motion in one plane to Select groups and motion in a plane at right angles thereto to find a line in a selected group, said signal associated with one of the branches,and means under the control of said automatic switch in the other branch for rendering said signal iiioperative over the trunk.

In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading to said switchboard and the other to said automatic switch` means for seizing;r said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condens-,cina signal at said switchboard-controlled b v said relay, a second relay connected with said trunlt on the. other side of said condenser, means at said manual switchboard for intcrmittcntl)7 energizing said second relay. means controlled by the operation of said second relay for controlling the operation of said automatic switch. lines divided into groups extendingr from said automatic switch. said switch having motion in one plane to select groups and motion in a plane at righ-t angles thereto to find a line in a selected group. said signal associated with one of the branches. and means under the control of said automatic switch in the other branch for rendering said signal inoperative over the trunk.

Signed by me at- Chicago, Cook county, Illinois, this 13th da)` of June. 1910.

i FRITZ LUBBERGER.

Witnesses:

EDWARD D. Farms, ARTHUR J. RM1 

